How it’s stored
When a vaccine is too hot or too cold, it becomes less effective or even inactive. If stored at the incorrect temperature, vaccine can be ruined or unsafe for use. Most vaccines require refrigerated storage at between 2 and 8C. Some vaccines require temperatures as cold as -20C. Some of the newer vaccines need to be kept ultra cold at -70C. For frozen vaccines some of them can be safely stored for a limited time between 2 and 8C. Regular refrigeratours cannot maintain an even temperature consistently, so specialized medical refrigerators are rquired for these precious products.